The invention pertains to a method and apparatus for mixing compounds that have at least one component isolated from reactivity until just before dispersing the active component or components. This dispersion process may be initiated by physically mixing or by physical mixing in combination with applying an ultrasonic nozzle or probe nearby or into the mixture. The active components may be isolated by several techniques including microencapsulation, coating with inert or inactive material and/or active material, agglomeration and other protective films which can be removed or broken by agitation or solvents or other chemical attack, or with sonic and/or ultrasonic signals of various specific frequencies depending on the application. In one application, powdered or agglomerated particles can be mixed with a water-based mastic just before dispensing. The agglomerated particles may in turn be coated with at least one passive (time release) or active material. The active species may contain any materials which upon contact with the liquid material will foam and expand and/or an adsorbent material which chemically or physically binds the water in the liquid to prevent shrinking and enhance drying in thick applications of the mix into locations often difficult to dry. This invention also pertains to all applications of this technique.
One application of the invention pertains to various fire stops and other penetration seals for application of sealing walls, slots, and floor penetrations for cable trays, conduits, pipes, cables and other penetrations. Parts of the penetration seals are designed to hold water, pressure, radiation, and prevent chemical, radiological, and bacterial contamination. The application of these fire stop-seals are to power plants, military facilities, ships, offshore energy facilities, chemical and other energy facilities, and other installations requiring penetration seals/fire stops. These seals have the advantage of low ampacity derating on electrical cables, easy installation, low cost, easy retrofit, easy modification, seismic resistances, resistance to radiation, chemical and biological agents as well as fire protection. These properties have become important in collective protective system (CPS) aboard military ships. These CPS areas protect the crew from radiation, chemical and biological weapons contamination.
Electrical cable fire stop protection has been recognized as important for many years, but the advent of nuclear power and Brown's Ferry Reactor accident has led to improved fire stop and penetration seal systems for all applications. Reg. Guide 1.75 September 1978 Revision 1 clearly describes the need for separation of electrical circuits such that no single failure will result in a loss of protective function. Appendix R and IEEE Standard 279-1971 are also concerned with separation and safety protection. THERMO-LAG subliming compound has been used to accomplish the dissipation of heat from fire and other sources, U.S. Pat. No. 3,022,190. THERMO-LAG is a registered trademark of Thermal Science Incorporated (TSI, Inc.). There are today several approved THERMO-LAG systems which meet electrical standards set by the safety shutdown systems of nuclear power plants and which meet the guidelines described in Appendix R and Reg. Guide 1.75; however, there is no approved penetration seal using any THERMO-LAG products or other water-based thermal protective compounds. One reason is because the material shrinks as it dries. Therefore to prevent cracking, the material must be applied in many thin layers, allowed to dry and then reapplied. This takes many weeks and much costly labor and is not costcompetitive or desirable.
Several standards exist for Various Penetration Fire-Stops including Underwriters Unlimited "Fire-Testing Penetration Fire-Stop", UL 1479, IEEE Standard for "Cable Penetration for Fire", IEEE 63, and ASTM E-814.
Silicone foam material, which expands in place, and other similar compounds are used for penetration seals throughout the industry although it takes up to nine inches thick to equal two to three inches thick of Ultraseal THERMO-LAG/three component mix fire barrier. Silicone foam burns and emits toxic products. Many penetration seal systems exist that meet E-119 fire stops test for one-and three-hour fire walls. These are expensive because of the large quantity of material and time required to completely fill the gap in the wall with a fire resistant material. The silicone form requires precision cut and fit damming boards on both sides of the opening which take a great deal of time to prepare and place and therefore are very costly. These materials (e.g., silicone foam) are usually good insulating materials and since that requires as much as nine inches of sealing length to obtain a three hour rating, the cable often must be derated because the insulated region caused a hot spot in the cable.
On military ships the added thickness and weight are problems because of the need for additional space and the importance of a low center of gravity and light weight. Therefore, there is a need for a low cost, low weight, low volume, vibration-resistant, easily repaired, rapidly sealing, expanding, easily installed, non-toxic, non-burning, and waterbased penetration fire stop and seal. There is also a requirement in certain applications to add additional cables or other penetrating objects, without the use of sharp drills or other similar devices.
Thus, there is a need for a foam in place penetration material which does not require a custom fit damming system and that will be less expensive, easily installed, weighs less, smaller volume, and minimizes effects on ampacity.